Turbine



K. BAUMANN.

TURBINE.

APPLICATION FILED MAY 3, 1919.

Patented Dec. 14, 1920.

2 SHEETS-SHEET I.

'NVENTOR K. BAUMANN.

TURBINE.

APPLICATION FILED MAY 3, 1919.

1,362,074. Patented Dec 14 2 SHEETS-SHEET 2- Z I EEOUJJ UNITED STATESPATENT OFFICE.

KARL BAUMANN, OF URMSTON, ENGLAND, ASSIGNOR TO THE BRITISH WESTING-HOUSE ELECTRIC AND MANUFAOTURING OUD'IPANY LIMITED, A CORPORATION OFGREAT BRITAIN.

TURBINE.

Application filed May 3, 1919.

To all whom it may concern.

c it known that I, KARL BAUMANN, a citizen of the Confederation ofSwitzerland, and a resident of Urmston, in the county of Lancaster,England, have invented a new and useful Improvement in or Relating toTurbines, of which the following is a specification.

This invention relates to turbines and more particularly to the rotorsor movable blade carrying elements of turbines in which the movingblades are attached to disks, wheels or the like, mounted on the rotorshaft. As at present constructed such disks, wheels or the like, areusually shrunk and keyed on the shaft with the result that the torque istransmitted from the disk or wheel to the shaft but not the centrifugalforces of the blades and the disk or wheel. With this construction thedisk, wheel or the like must be of sufficient strength to take all thestresses due to centrifugal force.

In those cases in which the diameter of the disk is comparatively smalland the bore relatively large, it is difficult to construct a disk ofsufiicient strength to take the centrifugal forces. A further dificultyresides in the fact that in order to prevent such a disk from becomingloose on the shaft when running at a high speed it is necessary toemploy a considerable shrinkage fit between the disk and the shaft,which increases the difliculty of assembling and disassembling the disksfrom the shaft.

The present invention has for its object to provide an improved turbinerotor or movable blade carrying element in which the above mentioneddisadvantages are overcome and the weight of the rotor can beconsiderably reduced, and according thereto the blades are attached tothe disk or wheel, or to a plurality of ring segments forming togetherthe equivalent of a disk or wheel in any suitable or well known way andthe disk or wheel, or segments as the case may be, are connected to theshaft of the rotor in such a manner that the whole or the greater partof the centrifugal forces of the blades and of the disk or segments willbe directly transmitted to the shaft.

In carrying out the invention the method of attachment of the blades tothe disk or segments and of the disk or segments to the shaft may be ofany suitable type, the two attachments being, however, essentially sep-Specification of Letters Patent.

Patented Dec. 14, 1920. Serial No. 294,542.

arate and independent of one another, and such that the centrifugalforces and forces due to the torque are transmitted from the bladeattachment to the disk attachment through the disk or segments(hereinafter referred to as the blade holder) as directly as possible,preferably though not necessarily in a substantially radial direction.The attachment between the blade holder and the shaft must be ofsufiicient strength to take, in addition to the centrifugal forces ofthe blades and of the blade packers, if any, those of the blade holderitself.

In the accompanying drawings, the several figures of which arehereinafter described in detail, various constructional forms which theinvention may assume are indicated diagrammatically, the same referencenumerals being used to indicate like parts throughout the variousfigures.

In Figure l the turbine shaft is shown at 1 with a grooved collar 2formed thereon. The blade holder 3, consisting of two or more segments,is provided on its inner circumference with tongues 4, 4, adapted to fitin the grooves 5, 5 in the collar 2. The

blade holder is attached to the shaft collar by bolts or rivets 6passing through both the collar 2 of the shaft and the tongues 4, 4 ofthe blade holder 3. The turbine blades are indicated at 7 and may beattached to the blade holder 3 in any suitable and well known manner,the attachment for the blades shown in this figure comprising tongues 8,8 formed on the foot of the blade which are received intocircumferential grooves or recesses 9, 9 in the blade holder, and adouble row of rivets l0, 10.

In Fig. 2 the construction is very similar to that illustrated in Fig. 1except that the collar 2 on the shaft and the tongues 4;, 4 on the bladeholder 3 are of greater depth to permit of a double row of bolts orrivets 6, 6 being employed, thus providing an attachment of greaterstrength between the blade holder and the shaft.

In Fig. 3 a construction of greater strength than that illustrated inFigs. 1 and 2 is secured by increasing the thickness of the blade holder3 as illustrated where it is attached to the shaft.

The segments comprising the blade holder 3 may either be made in onepiece, as illustrated in Figs. 1 to 3, or may consist of a plurality ofplates arranged side by side as shown in Fig. 4. Where, as will usuallybe the case, a plurality of blade holders are mounted side by side onthe shaft it may sometimes be found convenient to use one set only ofrivets or bolts 6 passing through all of said blade holders and thecollars on the shaft.

In the forms of the invention shown in the preceding figures the bladeholder 3 must be made in not less than two parts to allow of itsinsertion in the grooves on the collar, but may be made in a greaternumber of parts if desired. Alternatively, the blade holder may have buta single groove on its inner circumference into which the collar orflange on the shaft fits, the blade holder thus straddling the collar onthe shaft. However, for most conditions occurring in practice thisconstruction would not usually be'sufiiciently strong, and one or otherof the constructions illustrated in Figs. 1 to 4 will generally be foundpreferable.

In these constructions, in addition to the radial pull on the attachmentbetween the blade holder and the shaft there will also be a pull in atangential direction which will be most evident on the rivets or boltsnearest to the joints between the segments of the blade holder, and inorder to keep this pull as small as possible radial slots 11, as shownin Fig. .5, may be formed in the blade holder 3. Another convenientprocedure is to assemble the blade holder segments with initial tensionby heating the shaft while the blade holders are being assembledthereon.

Fig. 6 illustrates another construction in which the blade holder 3,formed of a number of segments as before, is assembled on the shaft 1 inan undercut groove 12, a portion of the shaft 1 adjacent to said groovebeing cut away to permit of the last seg ment of theblade holder 3 beingplaced in position, such cut away portion being then filled up by a stopor filling piece 13 secured to the shaft by screws 14 in a well knownmanner.

Fig. 7 illustrates another form of attachment between the blade holderand the shaft. In this form of the invention a collar 15 of dove-tail orT shape is formed on the shaft 1 of the rotor of the turbine, and theblade holder 3 is provided on its inner edge with a correspondingdovetail or T shaped collar 16. lChe blade holder is attached to theshaft by claws or plates 17, 17 furnished with grooves adapted 'toengage the collars 15 and 16 onthe shaft and on the blade holderrespectively, the claws or plates 17, 17 being secured together byrivets or bolts 18, 18 some or all of which latter may, if desired, alsopass through the collars 15 and 16 on the shaft and blade holder.

Fig. .8 illustrates a modification of the attachment shown in Fig. 7,the inner surface of the collar 16 on the blade holder 3 resting on theouter surface of the collar 15 on the shaft 1, the claws or plates 17,17 then having but a single groove embracing the outstanding flanges ofboth the collars 15 and 16. With this construction a single row ofrivets 18 connecting the two plates 17, 17 and lying, as shown, partlyin the collar 15 and partly in the collar 16 will generally be foundsufficient.

In some cases, as illustrated in Fig. 9, the claws 17, 17 betweenadjacent blade holders 3, 3 may be held in position by means of distancepieces 19 inserted between adjacent claws 17. l Vith this construction afilling. piece is used to hold the last segment of the distance orpacking piece in position in a manner well known.

A constructional form of the invention which differs from thosedescribed in the preceding figures is illustrated in Figs. 10 to 15inclusive. In this form of the invention the shaft 1 is provided withaxially alined grooves 20, the segments 3 forming the blade holder beingprovided on'their inner edges with projections 21, adapted to slide inthe grooves 20. The shape of the grooves 20 may vary, the projections onthe segments 3 being formed to'correspond. In Fig. 10 the grooves 20 areof mushroom shape, the projections 21 being formed correspondingly,while in Fig. 13 the grooves and projections are of dove-tail shape. InFig. 11 rectangular grooves are illustrated and in Fig. 12 grooves of- Vshape. In the latter cases the segments 3 are maintained in position inthe grooves by means of suitable pins, wedges or the like indicated at22.

In Figs. 10 to 13 the blading is not shown but this may be attached tothe segments forming the blade holder 3 as shown either in Figs. 14 or15, or in any other well known and suitable manner.

Still another manner in which the'invention may be carried into effectis illustrated diagrammatically in Figs. 16, 17 and 18. Asv hereillustrated the shaft 1 has formed around its circumference a pluralityof transverse rectilinear grooves 23, the inner edges of the segments 3forming the blade holder are furnished with corresponding rectilinearprojections 24 and are slid into position in the grooves 23 on theshaft. The grooves 23 on the shaft may be, as shown in Fig. 18, ofundercut or dove-tail shape, the

inner edge of the segments 24 of the blade holder being correspondinglyformed, or the segments 3 may be held in position in the grooves 23 onthe shaft by means of suitable pins or wedges 25 as illustrated in Fig.17. If, as illustrated, the blade holder 3 consists of four segmentsthree of them may be assembled on the shaft in the manner describedabove by being slid into position on the grooves 23, the fourth segmentbeing inserted radially in a plain groove, 2'. e., not undercut, andheld in position therein by wedges, screws or the like. The constructionillustrated in Fig. 16 is not limited to the employment of a bladeholder consisting of four segments as six, eight or any other number maybe used, a corresponding number of rectilinear grooves being formedaround the shaft.

If desired, all of the blade segments 3 may be secured in their grooveson the shaft by means of keys or wedges 25, in which case the bladeholder may conveniently consist of only two segments, two sets of keysor wedges being employed in connection with each segment, the keys ofeach set being arranged in an approximately tangential direction and atan angle of 90 relatively to one another, though it may sometimes befound desirable to employ a greater number of keys for each segment ofthe blade holder.

Where the segments of the blade holder are secured to the shaft bytangentially disposed keys or wedges, as described above, the groove onthe shaft may be circumferential, the inner boundary of the segmentsbeing formed to correspond as indicated in Fig. 19. In this figure theblade holder consists of two segments, only one of which is, however,illustrated, and is held in posit-ion in a circumferential groove 23 onthe shaft 1 by keys 25 driven in tangentially.

Although in the several forms of the invention illustrated in thedrawings the blade holders are shown as carrying only a single row ofblades it is to be understood that the invention is not limited in thisrespect as in some cases it may be found convenient.

to mount two or more rows of blades on a single blade holder.

I claim as my invention.

1. In a turbine, the combination of a rotor shaft and blade holdingmeans secured thereon, the securing portions of the shaft and bladeholding means being capable of transmitting centrifugal forces whollyradially to the shaft.

2. In a turbine, the combination of a rotor shaft, blade holding meanssecured thereon, and blades secured to the holding means, theconnections between the blade holding means and shaft and between theblades and blade holding means being capable of transmitting forceswholl radially from the blades to the blade ho ding means and from thelatter to the shaft.

3. In a turbine, a rotor element, a blade holding element, connectingmeans for the elements having interfitting portions and including meansto transmit radial forces from one element to the other, the portions ofone element being symmetrically disposed with reference to the portionor portions of the other element whereby centrifugal forces aretransmitted radially from one element to the other without thedevelopment of unbalanced lateral forces.

4:. In a high speed mechanism, the combination of a rotor shaft, anelement carried by the shaft, connecting means between the shaft andelement to transmit radial forces from the element to the shaft, saidconnecting means including interfitting portions with balanced radialtransmission means whereby the resultant of all radial forces are in aplane normal to the rotor axis.

5. In a high speed mechanism, the combination of a rotor shaft, a meansadapted to be secured to the rotor shaft including segments, means tosecure the first-named means to the shaft including interfittingportions carried by the shaft and each segment with means to transmitradial forces from each segment to the shaft.

6. In a turbine, the combination of a rotor element, blade carryingmeans on the rotor comprising segmental elements, and interfittingportions carried by the rotor and segmental elements, one element havingan odd number of portions and the other element an even number ofportions, together with means to transmit centrifugal forces from thesegmental elements to the rotor elements.

In testimony whereof I have hereunto subscribed my name this 31st day ofMarch 1919.

KARL BAUMANN.

